67Dart273 said

With manual control (toggle) of the OD you can put it in OD in 2nd. But at least with the 727 based ones, the difference between 2 gear in OD or 3rd without OD amounts to nearly the same thing.

I'd have to look up the ratios. I don't remember "whut" anymore.

Click to expand...

mbaird said

I had no idea the OD could engage in any gear except 3rd.
Makes sense I guess .
I have the solenoids for my 46rh . Should be in the car by spring ..

Click to expand...

autopar3000 said

I find it interesting that you have your OD set up to lock so late. What differential gear are you running?

I had that same type of pressure switch setup in my car with a 46rh. I had the pressure switches adjusted for "normal" acceleration, so it went into OD at about 50 mph and lockup at about 55 mph (3.23 gear, 26" tire). Of course, if I was going to do any sort of spirited acceleration I would have to manually shut off OD and LU ahead of time, otherwise I would be shifting to OD and locking up as soon as it shifted into 3rd gear, which could be way too early.

But mine wouldn't unlock at those same speeds. It unlocked when I hit about 50 mph (about 1500 rpm), and it wouldn't drop out of OD until I hit about 45 mph (about 1300 rpm). I guess that's just how my pressure switches worked; the pressure to close the circuit was X and the pressure to open the circuit was X minus a bit.

I'm running factory Magnum EFI, so I eventually got rid of the pressure switches and wired the computer to control the OD and LU. I was pretty surprised how quickly the computer would tell it to go into OD and LU during light acceleration. During light acceleration 3rd only lasts about 1 second, it will shift into OD almost immediately and put the RPMs at about 1200. If I keep accelerating gently or start cruising it will lockup and end up at about 1300 rpm (about 45 mph). I thought that was super low and there must be a problem, then I found this in the 1995 service manual:

View attachment 1716316071

Click to expand...